Less than 48 hours after switching to all-electronic tolls, Golden Gate Bridge officials called the conversion a success Thursday. But they are bracing for increased confusion and delays during the weekend, a time when more drivers have typically paid their tolls with cash.

"It's not commute traffic," bridge spokeswoman Mary Currie said of the weekend traffic. "It's a different profile."

In the hours after the new system was launched Wednesday morning, traffic moved smoothly past the now-shuttered tollbooths, but officials were concerned when some drivers failed to slow down, moving as quickly as 60 mph.

The electronic conversion brought little change for the 70 percent of drivers who already used FastTrak, the electronic toll system introduced on the bridge in 2000. During the morning commute, as many as 86 percent of drivers use FasTrak, but usage drops to 59 percent on Saturday evenings, according to the bridge district.

The district will dispatch employees to monitor the toll area this weekend and use loudspeakers to instruct confused drivers to keep moving, Currie said.

Under the new $3.2 million all-electronic toll system, FasTrak users can now pass through any lane except the carpool lane, which is second from the left.

Other drivers are charged using cameras that detect license plate numbers and run them through registration databases. Drivers can set up license plate accounts, prepay tolls with cash at kiosks or wait to receive bills in the mail.

Dietrich Stroeh, a bridge district board member who lives in Novato, said he has received positive feedback about the new system.

"It works pretty darned well," he said. "I've had a number of people say to me, 'It's the greatest thing since sliced bread.'"